The present invention relates to a non-contact power supply apparatus which can feed a power to each load from a feeder line of a primary circuit connected to an alternating current power supply via a pickup portion of a secondary circuit magnetically coupled to the feeder line in a physically non-contact state, and to a pickup portion used therein.
Conventionally, various handling systems have been employed such that a baggage is carried by using a carrier vehicle moving along a guide rail, and thereby, physical distribution has been effectively performed in a factory, a warehouse or the like. In general, a traction motor is used to tract such a carrier vehicle, and a drive power is supplied to the traction motor via a feeder line which is laid along the guide rail, and through which an alternating current flows.
In this feeding method, there are conventionally a trolley type and a non-contact type. The trolley type is a system in which a collector provided on the carrier vehicle side contacts with a feeder line so as to feed an electric power. On the other hand, the non-contact type is a system in which a pickup portion provided on the carrier vehicle is arranged in the vicinity of a feeder line, and then, an induced power is generated in the pickup coil so as to obtain an electric power. The above trolley type requires maintenance because the collector is worn, and further, has a problem that dust and spark are generated. On the contrary, the non-contact type has no problem as described, and therefore, a non-contact type power supply apparatus has been frequently used.
FIG. 1A is a schematic view showing a conventional monorail type handling system, FIG. 2 is a schematic view showing a non-contact power supply apparatus used in the conventional monorail type handling system shown in FIG. 1A, FIG. 3 is a schematic side view showing a structure of a conventional carrier vehicle, and FIG. 4A is a schematic side view showing a relationship between a feeder line and a pickup portion provided on the carrier vehicle.
In FIG. 1A, FIG. 2, FIG. 3 and FIG. 4A, a reference numeral 1 denotes a guide rail of a monorail type handling system in a factory, 2 denotes a carrier vehicle, and 3 denotes a system controller. The guide rail 1 is formed into a multiple loop which is constructed in a manner of connecting each station (not shown) in accordance with a handling purpose, and is located on plane. Each crossing portion is provided with a switch/rail type diverge/merge portion 4 for selectively using either rail.
As shown in FIG. 4A, the guide rail 1 is formed into a substantially I-letter shape in its cross section in a manner that a support column portion 1p is stretched between an upper plate portion 1u and a lower plate portion 1d, which are parallel with each other. Further, one side of the guide rail 1 is attached with a support arm (not shown) at its one side with an approximately regular interval in a longitudinal direction, and thus, the guide rail 1 is located in a state of being suspended from a ceiling or the like of a factory via the support arm. A feeder line 5 constituting a power supply section is fixed to another side of the guide rail 1 over the entire length thereof in the longitudinal direction, and is connected with a power source section 6.
The feeder line 5 is arranged like a loop in a manner of being laid on each distal end portion of a pair of upper and lower many supporters 1a fixed to the side face of the guide rail 1. Further, the feeder line 5 is constructed in a manner that insulated single wires are bundled so as to form a twist wire and that the twist wire is coated with a resin material. On the other hand, the carrier vehicle 2 is constructed in a manner that a carrier 23 for detachably mounting a handling produce is suspended from a pair of front and rear vehicle body frames 21 and 22 having a U-letter shape as shown in FIG. 3.
The vehicle body frame 21 includes a drive trolley 21a which rolls in contact with the guide rail 1 at a position opposite to an upper surface of the upper guide rail 1, and a pair of swing preventive rollers 21b and 21c which individually roll in contact with both upper and lower surfaces of the guide rail 1 at a position opposite to these surfaces. Further, the vehicle body frame 21 is provided with a motor M connected to the drive trolley 21a at its upper portion. Moreover, a pickup portion 24 as shown in FIG. 4A is provided at a portion opposite to the feeder line 5 of the guide rail 1 in the vehicle body frame 21.
The pickup portion 24 comprises a pickup core which is formed into an E-letter shape when viewing from its side, and the pickup core is constructed in the following manner. More specifically, in the pickup core, an upper plate portion 24b, a lower plate portion 24c and an middle plate portion 24d are arranged in parallel with each other, and are extended individually from upper, lower and intermediate portions of a back plate portion 24a made of a magnetic material and having a rectangular shape. Further, coils 24e and 24e comprising a litz wire are wound around each of upper and lower portions of the back plate portion 24a divided by the middle plate portion 24d. 
Each feeder line 5 is positioned and set in two concave portions of the above pickup portion 24 having an E-letter shape when viewing from its side and in a state of being close to each coil 24e;24e. An induced power is generated in each coil 24e;24e by an electric power supplied to each feeder line 5, and then, is supplied to the motor M via a power conversion section 7 as shown in FIG. 2.
The induced power generated in each coil 24e varies depending upon a length of the pickup core (a length in an extending direction of the feeder line 5) so long as the number of turns of the coil 24e and a power supplied to the feeder line 5 are the same. Thus, it is general to employ a method of varying the length of the pickup core in accordance with a power required for a load side and an incoming capacity of the coil 24e so as to obtain a required power.
By the way, when the length of the pickup core is determined, swing angles xcex1 and xcex2 (xcex1: vertical (upper and lower) swing angle as shown in FIG. 4B, xcex2: transverse (right and left) swing angle as shown in FIG. 4C) are determined. The swing angles are a condition for making no interference of the pickup core with the feeder line 5 from an interval between the upper plate portion 24b and the middle plate portion 24d, an interval between the middle plate portion 24d and the lower plate portion 24c, and an interval between the feeder line 5 and each coil 24e in the pickup core, or the like.
In order to make large the swing angles xcex1 and xcex2, it is necessary to wider set the aforesaid intervals between the upper plate portion 24b and the middle plate portion 24d, between the middle plate portion 24d and the lower plate portion 24c, and between the feeder line 5 and each coil 24e. However, when these intervals are set wider, the pickup core itself is inevitably formed into a large size. Moreover, an air gap is enlarged, and thereby, a magnetic resistance becomes large; as a result, a problem has arisen such that an incoming capacity is reduced. Therefore, in the case where the pickup core is constructed in the manner as described above, the swing angles xcex1 and xcex2 are set as follows. More specifically, the swing angle xcfx81 is merely set to such a degree that the carrier vehicle 2 is capable of being turned along the guide rail 1 in a horizontal plane; on the other hand, the swing angle xcex1 is merely set to such a degree that an error when attaching the carrier vehicle 2 to the guide rail 1 is avoided. For this reason, an arrangement pattern of the guide rail 1 is limited within a range similar to a substantially horizontal plane as shown in FIG. 1A. In particular, it is difficult to make an arrangement pattern of the guide rail 1 as shown in FIG. 1B having a difference in a height, and therefore, there is a problem that a degree of freedom is remarkably limited.
FIG. 5A is a schematic side view showing a construction of a conventional another pickup portion disclosed in Japanese Patent Application Laid-Open No. 9-252552(1997). In FIG. 5A, a reference numeral 1 denotes a guide rail, 5 denotes a feeder line laid along the guide rail 1, and 24 denotes a pickup portion.
The pickup portion 24 comprises a pickup core which is formed into a C-letter shape when viewing from the side, and the pickup core is constructed in the following manner. More specifically, in the pickup core, an upper plate portion 24b and a lower plate portion 24c are arranged in parallel with each other, and are extended individually from upper and lower edge portions of a back plate portion 24a having a rectangular shape. Further, convex portions 24g and 24g having a rectangular shape in its cross section are fixed to each surface opposite to distal end portions of the upper and lower plate portions 24b and 24c, and a coil 24e is wound around the back plate portion 24a. Furthermore, an interval between the convex portions 24g and 24g is set approximately equal to a diameter of the feeder line 5, or is set slightly larger than that.
In the above pickup portion 24, as shown in FIG, 5A, the feeder line 5 is positioned inside the pickup core having a C-letter shape in a state of being close to the coil 24e, and then, a support arm of the feeder line 5 passes through between the convex portions 24g and 24g together with a movement of the carrier vehicle 2.
By the way, in the conventional construction as described above, as a method of obtaining a power required for a load side, there are a method of enlarging an air-gap area of the pickup core, and/or a method of reducing the air-gap length of the pickup core. According to a method of making long a pickup core length in the method of enlarging an air-gap area of the pickup core, the pickup core is made into a large size. Moreover, according to a method of making small the interval between the convex portions 24g in the method of reducing the air-gap length, an interference with the supporter 1a need to be avoided; for this reason, there is the limit in a reduction of the air-gap length. In order to obtain a required power, the above method of reducing the air-gap length must be employed together with the method of making long the pickup core length; as a result, the pickup core is inevitably made into a large size. Therefore, as shown in FIG. 5B and FIG. 5C, there is a problem that a vertical swing angle xcex1 of the pickup core becomes small with respect to the feeder line 5, and also, a transverse swing angle xcex2 of the pickup core becomes small.
An object of the present invention is to provide a non-contact power supply apparatus which is suitable for three-dimensional running of a mobile such as a carrier vehicle or the like, and is compact and light with a simple structure, and further, can obtain a large incoming capacity, and to provide a pickup portion used in the non-contact power supply apparatus.
The pickup portion of the present invention generates an induced power, and includes a pickup core having a partially opening portion, and formed so as to surround a feeder line, a coil wound around the pickup core, and a pair of plate portions fixed individually to respective opening ends of the pickup core, and made of a magnetic material, each plate portion having an area larger than an area of portion fixed to each opening end. The non-contact power supply of the present invention is provided with the pickup portion having the aforesaid construction; therefore, it is possible to generate an induced power in the pickup portion on the basis of a power supplied to the feeder line.
In the present invention, the pair of plate portions made of a magnetic material and having an area wider than a fixing area are fixed to both opening ends of the pickup core surrounding the feeder line. Therefore, it is possible to reduce a width dimension of the pickup core, and to reduce an air gap between opening ends. Further, a magnetic path area is enlarged, and a magnetic resistance is greatly reduced, and thereby, a mutual inductance is increased, that is, an incoming capacity is increased. An allowable range in a change of orientation becomes large; therefore, the apparatus of the present invention is applicable to three-dimensional running of a mobile. Furthermore, it is possible to provide a small-size and light pickup core, and to improve a heat radiating effect, and to cheaply manufacture a pickup core.
Further, the pickup core is provided with an end portion which is formed integrally with a pair of plate portions arranged in parallel with the feeder line at an interval, at its opening portion. The pickup core has the end portion formed integrally with the plate portions at the opening portion; therefore, a manufacture of the pickup core is not troublesome.
Further, the pickup portion is constructed in a manner that a plurality of pickup cores are piled up in the form of plural stages in a state that respective opening ends are directed toward the same side so as to surround respective feeder lines. Therefore, the pickup cores surrounding the respective feeder lines are fixed in a state of being vertically piled up, so that an incoming capacity can be readily increased with a simple structure.
Further, the pickup portion is constructed in a manner that a plurality of pickup cores are arranged in parallel in a state that respective opening ends are directed toward the same side so as to surround a same feeder line. Therefore, the pickup cores are transversely arranged in a state that their sides are abutted against each other, so that an incoming capacity can be readily increased with a simple structure.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.